There is a current need in the field of auditory neurophysiology for a small high bandwidth telemetry system that will enable the recording of many channels of neural activity in unrestrained animals in response to natural acoustic stimuli. Such a system will provide a powerful tool that will be used to trace neural pathways that process species-specific vocalizations. The transmitter will provide up to 64 neural channels where each channel will be sampled at 50 KHz and will be 1 cm3 in size. It will be designed to allow up to eight simultaneous systems, which will permit researchers to study interactions, vocal exchanges, and communications between and among animals within a social group or colony. The transmitter will be designed to provide an interface to record acoustic signals from several small mounted microphones. Recording both acoustic and neural channels simultaneously will allow these signals to be correlated. Although the system will be targeted at auditory neurophysiology in marmosets, it will be general enough to be used in many neuroethology applications. [unreadable] [unreadable] Specific Aim 1: To develop a 5.8 GHz transmitter that is 1 cm2 in size and that consumes only 90mW of power. The transmitter will be designed to allow up to eight systems to occupy the 5.8 GHz ISM band simultaneously. [unreadable] [unreadable] Specific Aim 2: To develop an amplifier and multiplexer front end for 64 channels that will fit on several boards of size 1 cm2. This will be accomplished by a chip-on-board approach. This will allow the 5.8 GHz transmitter and analog front end to be 1 cm3 in size. [unreadable] [unreadable] Specific Aim 3: To develop a flexible on-line data analysis and Ethernet backend to the telemetry system so that functions such as spike sorting and/or reverse correlation can be performed in real-time as data is collected. [unreadable] [unreadable] Health Relevance: It is believed that studying the neuroethological aspects of communication sounds will contribute most to the understanding of how speech sounds are processed by humans. Studying how a vocally active primate can identify and extract behaviorally relevant vocalizations from other sounds will provide a model that will allow the development of signal processing algorithms that can extract speech signals from other non-speech sounds. This will have a direct impact on improving engineering applications such as robust speech recognition systems and hearing aids. [unreadable] [unreadable]